Washing machine with oscillating work support

ABSTRACT

A washing machine for workpieces includes a heated fluid sump tank having sides formed of inclined plates which meet at their lower edge and a manually rotatable screw conveyor disposed above the bottom edge to force sludge up a standpipe to clean the tank. The cover for the tank is hinged to the tank at one edge and supports a submersible pump so that it projects downwardly into the fluid in the sump. A washing compartment formed on the upper side of the cover includes a plurality of spray pipes through which wash fluid is forced by the pump. A work support consists of a plurality of rollers arrayed parallel to one another to form a roller conveyor section. The conveyor section is pivoted about a horizontal line and an oscillatory mechanism causes the support to reciprocate so that a workpiece is moved back and forth under the spray.

United States Patent [191 1 [1 11 3,776,246 Ballard Dec. 4, 1973 WASHING MACHINE WITH OSCILLATTNG WORK SUPPORT Primary Examiner-Robert L. Bleutge Attorney-Gerald E. McGlynn, Jr. et al.

[57 ABSTRACT A washing machine for workpieces includes a heated fluid sump tank having sides formed of inclined plates which meet at their lower edge and a manually rotatable screw conveyor disposed above the bottom edge to force sludge upa standpipe to clean the tank. The cover for the tank is hinged to the tank at one edge and supports a submersible pump so that it projects downwardly into the fluid in the sump. A washing compartment formed on the upper side of the cover includes a plurality of spray pipes through which wash fluid is forced by the pump. A work support consists of a plurality of rollers arrayed parallel to one another to form a roller conveyor section. The conveyor section is pivoted about a horizontal line and an oscillatory mechanism causes the support to reciprocate so that a workpiece is moved back and forth under the spray.

9 Claims, 7 Drawing Figures IAIENTEUBEB 4:975 3.776.246 SHEET 1 BF 3 ATTc-RNEY WASHING MACHINE WITH OSCILLATING WORK SUPPORT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to washing machines wherein the workpieceis subjected to a spray and the spent fluid is collected in a sump for cleaning, heating and return to the spray and more particularly to such machines when the workpiece is moved relative to the spray during the wash.

2. Description of the Prior Art A variety of washing machines have previously been used wherein a part to be cleaned is subjected to a fluid spray and the part is moved relative to the spray so as to allow the fluid to impact different areas of the workpiece surface.

Such machines are useful as dish washers; clothes washers, discrete part cleaners and the like.

From one design aspect these'machines may be divided into two classes: one, wherein the workpiece is maintained stationary and the spray is moved; the other wherein spray is stationary and the workpiece is moved. The first class of machines usually employ fluid pressure as a source of motive power for the spray heads and while this is an economically attractive solution it presents a number of problems in that clogging of the heads or a reduction in the fluid pressure will decrease the relative movement of the spray and the parts and generally degrade the machines performance. The class-of machines wherein the workpiece is moved relative to the spray heads has generally been regarded as providing superior cleaning action but these machines have often involved rather complex and expensive mechanism which is difficult to maintain and service.

A popular type of such washing machines employs a base in the form of an open top tank which serves as a sump for the cleaning fluid.. A work support is supported above the tank and the spray heads are arranged around the work support. The sprayed fluid collects in the sump where it may be filtered and heated previous to reuse. In such machines the access to the sump is generally very limited and difficulty is encountered in removing the sludge and grit which collects in the sump.

SUMMARYOF THE INVENTION The present invention contemplates a washing machine of the type wherein a workpiece is moved with respect to stationary spray heads which is simple in construction so as to be low in initial cost and reliable in operation. It further contemplates such a machine of the type wherein a work support and spray heads are supported above a fluid sump arranged to allow the work support and spray heads to be easily moved away from the sump to provide complete and ready access to the entire sump area. Moreover, the present invention contemplates an economical system for removing sludge from the bottoms of sumps from the outside of the machine, eliminating the need to open the machine to clean the sump. 7

According to one broad aspect of the present invention workpieces to be cleaned are supported on a substantially horizontal surface which is surrounded by spray heads. Means are provided to cause the workpiece to reciprocate along a linear path bounded by two opposed ends of the work support so as to provide relative movement between the sprays and the part. In a preferred embodiment of the invention the work support takes the form of a section of roller conveyor supported on a horizontal axis which is parallel to the axes of the rolls and aligned about the mid-point of the section. The section is adapted to be tilted in the manner of a teeter-totter about this axis and an oscillatory mechanism is provided which causes the work support to tilt first in one direction and then the other. Workpieces retained on the support thus tend to roll first in one direction and then the other. The movement of the workpiece on the support is limited by end stops which take the form of coiled springs in the preferred embodiment of the invention. The workpiece thus rolls in one direction until it hits the spring end stop and then rolls in the opposite direction when the oscillatory mechanism causes the work support to tilt in that direction.

In other embodiments of the invention alternate methods might be provided for causing the workpieces to reciprocate along the work support in accordance with the broad concept of the invention. For example, the work support could maintain a stationary horizontal attitude and the rolls could be powered in a reciprocating manner so as to move workpieces first to one end and then the other. Alternatively, mechanism might be provided to engage the workpieces and slides them in a reciprocating manner along a low friction work support surface.

The present invention further contemplates an extremely simple oscillatory mechanism for the work support which employs a pneumatic cylinder having its rod coupled to a torque arm fixed to the work support axis and a reversing valve which senses. the motion of the work support and reverses the power connections to the cylinder at the ends of the motion.

In order to allow the sump to be cleaned without disturbing operation of the machine in the preferred embodiment of the invention the walls of the sump are formed of a pair of inclined plates that meet at an angle to form a V-shaped trough at the bottom of the sump. Sludges and impurities which precipitate out of the cleaning fluid collect in this trough. A manually rotatable screw extends along this trough so as to move the sludge toward one end-of the sump when the screw is rotated. A vertical stand-pipe receives the sludge at the output end of the screw and raises it above the fluid level.

To provide ready access to the :sump the machine employs a sump tank having an open upper edge. A cover member for the tank is hinged to the tank along one line so that it may be pivoted away from the tank to provide access to the tank. This cover supports'a washing compartment having the spray heads and the work support fixed therein. The cover also retains a pump mechanism which has a head projected downwardly into the sump when the cover is closed. Thus, the entire operating mechanism of the washing machine may be lifted up to provide ready access to the sump.

Other objectives, advantages and applications of the prevent invention will be made apparent by the following detailed description of a preferred embodiment of theinvention. The description makes reference to the accompanying drawing, in which:

FIG. 1 is a perspective view of a machine formed in accordance with a preferred embodiment of the present invention with parts broken away to better illustrate the machine;

FIG. 2 is a sectional view through the washing tank of the machine of FIG. 1, taken along line 22 of FIG. 1, illustrating a part being washed;

FIG. 3 is a detailed perspective view of the work support of the machine;

' FIG. 4 is a detailed perspective view of the sludge collector and conveyor formed in the sump of the machine;

FIG. 5 is a perspective view of the interior of the machine with the cover and its associated mechanism lifted up to provide access to the sump;

FIG. 6 is a detailed perspective view of the oscillatory mechanism and associated pneumatic circuitry for rocking the work support; and

FIG. 7 is a detailed sectional view through the reversing valve of the machine, taken along line 7-7 of FIG. 6.

A preferred embodiment of the invention takes the form of a washing machine including a base consisting of a rectangular open topped tank 10 formed of welded sheet steel and having four leg blocks 12 affixed to its underside adjacent to its edges. The tank 10 has an outwardly projecting horizontally aligned lip 14 extending about the entire rectangular perimeter of its open top.

A cover member, generally indicated at 16, is adapted to be supported on the lip. The cover member is rectangular in shape and is framed by four angular steel strip sections 18 which border its four edges. The angle sections 18 are each arranged so that one of its flanges projects downwardly and the other flange projects outwardly from the plane of the top. The downwardly projecting flanges are so spaced as to fit interiorly of the edges of the lip 14. When the machine top is in a closed position as viewed in FIG. 1 the bottom sides of the outwardly projecting flanges of the angles 18 simply rest on the top sides of the lips 14 on three of the sides. On the fourth side, the rear of the machine is viewed from FIG. 1, the flange 18 is attached to the adjacent lip 14 by a piano hinge 20. This allows the top to be pivoted about the tank 10 into an open position as illustrated in FIG. 5.

The top 16 supports a submersible pump 22 on its undersideso that the pump projects into the tank 10 when the top is in a closed position. The input end of the pump 22 carries a filter member 24 which normally projects into fluid contained within the tank 10. A drive motor26 for the pump 22 is supported on the upper side of the tank 16 and has its shaft projecting down to the pump.

That section of the top 16 which supports the pump 22 is reenforced on its underside by a welded angle member 28 which extends the length of the top and a pair of reenforcing steel straps 30 which extend from the member 28 to the edge of the top. The pump is arranged midway along the long side of the top 16 adjacent to one edge thereof between the straps 30. A pair of removable cover members 32 are formed in the top on opposed sides of the pump 26 and allow access to the tank when the cover is in its closed position.

A washing compartment, generally indicated at 34, is formed on the top 16 along the side opposite to that occupied by the pump 26 and the covers 32. The washing compartment is formed by an insulated steel top 36 and a pair of insulated steel sides 38 and 40, each projecting along the long dimension of the tank. The ends of the washing compartment 34 are formed by a pair of doors 42 and 44 consisting of panels of insulated sheet steel hung to swing about vertical axes on the sidewalls of the wash compartment.

The longitudinal edges of the top 36 of the wash compartment are formed of a pair of steel plates 44 and 46 which have angles sides, truncated tops and lift holes 48 and 50 formed adjacent these truncated tops. The lift holes allow the top to be lifted by suitable hoist mechanism.

The top 16 is opened in the area below the wash compartment 34 so that the compartment communicates with the sump formed in the bottom of the tank 10.

The interior of the wash compartment 34 is defined by a plurality of spray tubes 50 which consist of metallic tubing elements bent into rectangular loops having dimensions complimentary to the interior of the compartment. These tubes are aligned normally to the length of the compartment 34 and are supported by brackets 52 suspended from the interior sidewalls 38 and 40 of the compartment. The spray tubes 50 are each formed with a plurality of spray apertures 54 formed along the interior surfaces of the loops so that all four sides of the loop send spray into the interior of the loop when fluid is passed through the tubes.

The tubes are connected to the outlet of the pump 22 by means of a manifold pipe 56 which runs the length of the tank 10 under the top 16 and is supported by downward tubular projections from the tubes 50. The manifold is connected to the pump 22 by a pipe 58. Accordingly, fluid pumped into the manifold 56 by the pump 22 is passed to all of the tubes 50 and is sprayed into the interior volume defined by the tubes. The spent fluid falls back into the sump formed by the tank 10 and is then recirculated through the filter 24 by the pump 22.

A workpiece to be cleaned is supported and moved through the spray thus produced by the tubes 50 on a work support, generally indicated at 60. The support consists of a roller conveyor section comprising a plurality of rollers 62 rotatably supported by a pair of angle iron side rails 64. The rollers 62 are arrayed parallel to one another and are joumalled for free rotation. A pair of horizontal guards 66 are supported above each of the rails 64 by a series of vertical posts 68. A pair of coil springs 70 are adapted to be supported by their hooked ends between a pair of the posts 68 on opposite sides of the work support 60 so as to form end retainers for workpiece 72 supported on the rollers 62.

The work support 60 is retained along the lower side of the wash compartment 34 on a shaft 74 which is fixed to the rails 64 and projects beyond the ends of the rails parallel to the rollers 62. One end of the shaft 74 is retained in bearings 76 formed in the outer side wall 38 while the other end of the shaft is retained in bearings 78 formed in the side wall 40.

As is best seen in FIG. 6, one end of the shaft 74 projects outwardly beyond the wash compartment wall 40 and has a normally disposed steel torque arm 80 affixed to its end. The torque arm 80 is reciprocated so as to cause the shaft 74 and the work support 60 to oscillate by 'a pneumatic cylinder 82 which is fixed to the side wall 40 of the wash compartment. The torque arm 80 is reciprocated through an angle of about 8 degrees so as to oscillate the work support between an inclination of four degrees with respect to the horizontal in one di rection and then four degrees with respect to the horizontal in the opposite direction. The gravitational forces acting on the workpiece 72 thus cause it to roll first to one end of the work support, until it abuts one of the springs 70, and then to roll to the other end of the worksupport until it abuts the other spring 70. This reciprocational along the work support provides the relative movementof the workpiece with respect to the spray that is required for the desired washing action.

The pneumatic cylinder 82 is caused to reciprocate by a circuit which is powered from an air line 84. A manual shut off valve 86 is normally in an open position and-an automatic valve 88 is normally closed but is opened when the pressure in a line 90, which senses the output pressure of the pump 26, reaches a predetermined level. A pressure valve 92 allows the manual reading of the pump pressure. The pump 26 is energized from suitable electrical circuitry contained within a panel 94.

'When the valve 88 is opened pneumatic pressure is provided through a one way check valve 96 to a pneumatic accumulator 98. The pressure is also applied to a filter and lubricator arrangement 100. The output of this circuitry is provided to a four-way toppet operated valve 102. Pneumatic pressure is provided through the valve 102 to the opposed ends of the cylinder 82 through a pair of lines 104 and 106. One of the lines receives pneumatic pressure while the other line is vented to atmosphere, the particular lines which are pressurized or vented depending upon the condition of the poppets of the valve 102.

As is best seen in FIG. 7 the valve 102 has a pair of poppets 110 and 112 extending from its opposite side. A valve operating arm 114 is fixed to the shaft 74 at right arms to the torque arm 80. Arm 1 14 carries a pair of brackets 116 and 118 which abut the opposite sides of the valve 102, adjacent to the poppets 110 and 112 respectively. When fluid power is provided to the cylinder 82 the shaft 74 is rotated through the torque arm 80 until one of the brackets 118 or 116 engages its adjacent poppet. Then fluid power is reversed to the lines 104 and 106 causing the torque arm 80 to reverse their rotation of the shaft 74. This produces a continual oscillation of the work support 60 while the pneumatic power is applied.

The piston rod of the cylinder 82 engages the end of the torque arm 80 by a trunnion joint 124. The same end of the torque arm 80 is normally locked in a fixed position by a shot pin 126 carried on the end of a pneumatic solenoid 128. The shot pin 126, when released, enters a hole in the end of the torque arm 80 and retains the torque arm in such a position that the work support 60 is horizontal so that work may be loaded onto and off of it through the doors 42 and 44. When the valve 88 is opened to admit pneumatic pressure, the shot pin in retracted by the solenoid 128 and allows the torque arm to freely move. When the pump 26 is shut off and the resultant lowering of fluid pressure closes the valve 88 the shot pin 126 moves against the end of the torque arm 80. The pneumatic pressure retained in the accumulator 98 continues to power the cylinder 82 until such time as the shot pin locks the torque arm against further motion, when the work support 60 reaches its horizontal position.

The interior of the tank is formed by a pair of sloping plates 130, 132 which are arranged in a V-shape so as to form a trough at their lower end. Sediment in the cleaning fluid and nonsoluble particles washed off of the workpieces tend to collect in this trough. A screw conveyor 134 is arrayed along the bottom of this trough and a handle 136 projects through the side wall of the base. The far end of the screw conveyor vents into a stand-pipe 138 (best seen in FIG. 4) which raises sludge moved by the screw conveyor up to above the fluid level where it can be manually removed. This minimizes the need for changing the cleaning fluid. A gas fired emersion heater 140 is retained within the tank 10 and vents to a stack 142 formed on the outside of the tank.

Having thus described my invention, I claim:

1. A part washing machine including a source of fluid; means for spraying the fluid through a volume; a work support having a generally horizontal elongated surface disposed in said volume; said work support comprising a plurality of roller elements rotatably supported on horizontal axes extending normally to the axis of elongation; and means for causing a part to be washed which is supported on said work support to repeatedly reciprocate between opposed ends of said support so as to move with respect to said spray.

2. The part washing machine of claim 1 including part stops at the opposed ends of said work support and wherein said means for causing said part to reciprocate between opposed ends of said support comprises means for pivoting said support about a. generally horizontal axis in an oscillatory manner so that the force of gravity causes the part to move first toward one part stop and then toward the other part stop.

3. The part washing machine of claim 2 wherein said work support includes anti-friction elements formed on its upper surface so that said part slides along said antifriction elements, under the force of gravity, as said work support pivots.

4. The part washing machine of claim 1 wherein said work support has an upper surface which has an exten' sion in the horizontal plane and includes anti-friction elements disposed on said surface and part stops disposed at the opposed ends of said work support to limit the motion of a part on the support.

5. The part washing machine of claim 1 wherein said work support includes an elongated horizontal surface adapted to pivot about a horizontal line normal to its extension in an oscillatory manner.

6. The part washing machine of claim 5 wherein the work support includes stop elements fixed to each of its ends and adapted to limit the motion of a part moving on said work support.

7. The part washing machine of claim 6 wherein said stop elements comprise coil springs extending normally to the longitudinal axis of said work support, above the roller elements.

8. A part washing machine including a source of fluid; means for spraying the fluid through a volume; a work support consisting of an elongated section of roller conveyor having the rolls disposed normally to the elongated axis, said work support being disposed in said volume; means for supporting said work support so as to allow pivoting motion of said support about a horizontal axis extending normally to the elongate axis of said section, adjacent to the middle thereof; means for causing said work support to pivot about said axis in an cillated. 

1. A part washing machine including a source of fluid; means for spraying the fluid through a volume; a work support having a generally horizontal elongated surface disposed in said volume; said work support comprising a plurality of roller elements rotatably supported on horizontal axes extending normally to the axis of elongation; and means for causing a part to be washed which is supported on said work support to repeatedly reciprocate between opposed ends of said support so as to move with respect to said spray.
 2. The part washing machine of claim 1 including part stops at the opposed ends of said work support and wherein said means for causing said part to reciprocate between opposed ends of said support comprises means for pivoting said support about a generally horizontal axis in an oscillatory manner so that the force of gravity causes the part to move first toward one part stop and then toward the other part stop.
 3. The part washing machine of Claim 2 wherein said work support includes anti-friction elements formed on its upper surface so that said part slides along said anti-friction elements, under the force of gravity, as said work support pivots.
 4. The part washing machine of claim 1 wherein said work support has an upper surface which has an extension in the horizontal plane and includes anti-friction elements disposed on said surface and part stops disposed at the opposed ends of said work support to limit the motion of a part on the support.
 5. The part washing machine of claim 1 wherein said work support includes an elongated horizontal surface adapted to pivot about a horizontal line normal to its extension in an oscillatory manner.
 6. The part washing machine of claim 5 wherein the work support includes stop elements fixed to each of its ends and adapted to limit the motion of a part moving on said work support.
 7. The part washing machine of claim 6 wherein said stop elements comprise coil springs extending normally to the longitudinal axis of said work support, above the roller elements.
 8. A part washing machine including a source of fluid; means for spraying the fluid through a volume; a work support consisting of an elongated section of roller conveyor having the rolls disposed normally to the elongated axis, said work support being disposed in said volume; means for supporting said work support so as to allow pivoting motion of said support about a horizontal axis extending normally to the elongate axis of said section, adjacent to the middle thereof; means for causing said work support to pivot about said axis in an oscillatory manner so as to cause parts disposed on said support to reciprocate between ends of said support so as to move said parts with respect to the spray; and work stop means arranged adjacent to each end of said work support.
 9. The part washing machine of claim 8 including means for supporting said conveyor section in a generally horizontal attitude at such time as it is not being oscillated. 